Mississippi navigator of forty horse-power

I am a man, sir, of forty horse-power, and 110 lbs. of steam. I was born in the state of Missouri, and raised in Illinois. I have lived in Chicago, and been as far east as New York, and as far west as Omaha. I have had a pressure of steam up to 120 lbs., but that was too high, and I have been reduced down to 60 lbs., and that is now the pressure in the hands of the United States government. I am employed in the navigation of the Mississippi, and am considered safe at high pressure, but unsafe at low. I am considered safe, however, at sixty pounds, and that is the power of steam under which I am navigating at present. I am not considered dangerous, except when up